Method comparison for calcium determination by flame atomic absorption spectrophotometry in the presence of phosphate.
We investigated the suppressive effects of phosphate on calcium determinations with lanthanum-air/acetylene and potassium-nitrous oxide/acetylene methods, and we evaluated the ability of these methods to meet the suggested analytical goals for urine samples. The 20 g/L La-air/acetylene method was the most nearly accurate for predicting the actual calcium concentrations (t-test value = -0.042), followed by the 2 g/L K-nitrous oxide/acetylene method (t-test value = 0.450), 10 g/L La-air/acetylene (t-test value = -0.733), and finally 5 g/L La-air/acetylene (t-test value = -2.446). The dilution used significantly influences the apparent calcium concentration measured with the La-air/acetylene methods.
Welch
M W
MW
Department of Pathology, Colorado State University, Fort Collins 80523.
Hamar
D W
DW
Fettman
M J
MJ
D000818:Animals; D002118:Calcium / Q000592:standards / Q000652:urine*; D002415:Cats; D002624:Chemistry, Clinical / Q000592:standards; D005188:False Negative Reactions; D006801:Humans; D010710:Phosphates / Q000592:standards / Q000652:urine*; D013054:Spectrophotometry, Atomic / Q000379:methods
D010710:Phosphates; D002118:Calcium